BioTensegrity – body mechanics

14 Dec
  • This is really interesting  as a model of biologic structures. Here is an article (edited for space reasons) by Stephen M Levin MD and others that hits on some key points.

 

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The Mechanics of Martial Arts

Eastern philosophy has not had a physical model for martial arts that a western trained mind could wrap a thought around. That is, not until biotensegrity.

The symbol of strength for western culture is the Greek god, Atlas. After a mythical war between the Olympians and Titans, Atlas, one of the losers, was condemned to stand as a pillar and support the universe on his shoulders for all eternity.

Following this model, strength, in western thought, is characterized as a rigid, unyielding and unmovable column. Western thought has the rigid column, the lever, and brute force, all concepts familiar to us since childhood when we built our first stack of blocks, rode a seesaw and smashed our first toy. In eastern thought, strength comes from deep within and is flexible, yielding and mobile; it flows. This difference in philosophy of strength is expressed in a difference in approach to combat sports. But eastern philosophy has not had a physical model for martial arts that a western trained mind could wrap a thought around. That is, not until biotensegrity. Biotensegrity is a mechanical model of biologic structure and function based on construction concepts introduced by Kenneth Snelson and Buckminster Fuller in the 1960s. In these models, the compression struts or rods are enmeshed and float in a structured network of continuously connected tension tendons. The shafts constructed by tensegrity networks are as different from a conventional column as a wagon wheel differs from a wire spoke bicycle wheel. Let me explain.

A conventional column is vertically oriented, compression load resisting and immobile. It depends on gravity to hold it together. It can only function on land, in a gravity field. The heavy load above fixes it in place. It must have ground beneath it for support. The weight above crushes down on the support below and the bottom blocks must be thicker and stronger than what is above it. If the spine is a conventional column, the arms and legs will cantilever off the body like flagpoles off a building. Moving an up-right, multiply hinged, flexible column, such as the spine as envisioned in conventional biomechanics, is more challenging than moving an upright Titan missile to its launch pad. Walking and running have been described as a controlled fall, a rather inelegant way to conceptualize movement. It certainly doesnt describe the movement of a basketball player, a ballet dancer or a martial arts master. In the standard spine column model, the model for mobilizing the spine and putting the body in motion would be a wagon wheel.

In a wagon wheel, each spoke, compressed between the heavy rim and the axle, acts as a column. The wheel vaults from one spoke/column to the next, loading and unloading each spoke in turn. The weight of the wagon compresses the single spoke that then squeezes the rim between the spoke and the ground. At any one time, only one spoke is loaded and the other spokes just stand there and wait their turn. The spoke must be rigid and strong enough to withstand the heavy compression load and short, thick spokes do better than long, thin ones. The rim must be thick and strong, as it would crush under heavy load as it, too, is locally loaded. The forces are generated from the outside to the center. Using the column, post and lintel model, in a standing body, the heel bone would have to be the strongest bone in the body instead of, as it is in life, one of the weakest and softest. Biotensegrity bodies would be like a wire-spoke bicycle wheel . In a wire wheel, the hub hangs from the rim by a thin, flexible spoke. The rim would then belly out if it were not for the other spokes that pull in toward the hub . In this way, the load is carried by the tension of the many spokes, not the compression strength of one. The load gets distributed through the system and the hub is floating in a tension network like a fly caught in a spider web. All spokes are under tension all the time, doing their share to carry the load. They can be long and thin. Even loads at the rim become distributed through the system so the rim does not have to be thick and strong as in a wagon wheel. The structure is omni-directional and functions independent of gravity. Unlike a conventional column, it is structurally stable and functional right side up, upside down or sideways. A tensegrity structure can function equally well on land, at sea, in air or space. Now think of each cell in the body behaving structurally as if it were a three-dimensional bicycle wheel. Each wheel would connect to each adjacent wheel the cell level, up the scale to tissue, organ and organism, a wheel within a wheel within a wheel.  In this system all connective tissues in the body work together, all the time. It known, by recent experimental work that all the connective tissue, muscles, tendons ligaments right down to the cells are interconnected in just this way.

The body model would be more like Snelsons Needle Tower where the bones of the tower are enmeshed in the wire tendons, never touching or compressing one another. Unlike flagpoles attached to the side of a building, the limbs are integrated into the system. The energy flows from deep within the structure, chi, out to the tips of the fingers and toes. The basic building block of the biotensegrity structures, the finite element, is the tensegrity icosahedron.

We neednt go in to all the details of the evolution of the biologic body here, but there are some very special properties of the icosahedron that explain the particular characteristics of biologic structure. It is, mathematically, the most symmetrical structure and, in its resting state, is extremely energy efficient. Distorting the shape requires energy and when that energy is released, it returns to its least energy state, a, normally, self-regulating and self-generating mechanism. It is like a spring that, when distorted, will bounce back to its original shape. But it is a very special spring. When a steel spring is in its resting state, there is no energy storage. Adding a weight, say a kilo, will stretch the spring a defined amount, say 10cm. Each additional kilo will stretch the spring an additional 10cm. When the spring is released, all the stored energy is immediately released and the spring will snap back. If it is not restrained, it will bounce because of the accelerated motion. And, depending on how springy elastic it is, it will bounce and bounce and bounce, jerking up and down. This is the type of spring associated with the standard column, post and lintel construction of the body in western mechanics and is characterized as linear behavior.

The icosahedron, tensegrity spring is different and characterized as nonlinear. In the resting state, there is always some residual tension or tone in the system so it is never completely relaxed. If you add a kilo weight it may distort 15cms. But add another kilo and the distortion may only be 7cms, then 4cms, then 1cm. The icosahedron spring gets stiffer and stronger as you load it.

You can see that as you add more weight a great amount of energy can be stored with very little change of shape of the icosahedron spring. When released, there is not the sudden, total release of stored energy as there is in a linear spring, but a great amount of energy can be released early and the last part can be released slowly and gently; a splashdown rather than a hard landing. This softens the blow and removes the bounce and jerkiness. As noted, not all the energy is released, some remains in storage. Grab onto your earlobe and pull. At first it distorts easily, but then it stiffens and pulling on it doesnt change the shape very much. Let go. It regains most of its original shape quickly, but the last bit is very slow. It does not bounce back like a rubber band and slap you on the side of the head. This is often termed in biomechanical circles as visco-elastic as it has properties that in some ways are like fluid and in other ways, like a stiff elastic spring. In biologic bodies with bones, the stiffest icosahedrons are the bones and the most energy can be stored there. When compressed or expanded the movement of the icosahedron is helical, like the threads of a wood screw, and this is consistent with what we know of normal body movement. When it behaves as a stiffening fluid, it becomes a shock absorber, soaking up the energy rather than focusing it.

Those of you who are martial art practitioners already know you dont stand stiff and upright but move in all directions like a break-dancer. You know that the energy flows in and out from deep within the system and that you can bring energy up from the squishiness of your cells out to harden on the tips of your fingers. Your body is never completely flaccid; some tone always remains in the system. To get the maximum energy you screw yourself down and then explode with tremendous force from within, but never overshoot your mark. Pulling the force from deep within your structure is recruiting the entire body mass. Newton’s second law of motion is force equals mass times acceleration F = ma. Imagine the difference if a small car moving at 5MPH strikes your automobile or a bus moving at 5MPH strikes your auto; quite a difference. Consistent with that law, striking a blow with your whole body creates a greater force than just striking with your fist, as you are increasing mass. In the standard post and lintel model, the arm and fist are just hanging off the body mass and operate independent of it. In a conventional boxers blow, speed a is all-important as the mass m is mostly the fist, in the biotensegrity model, the entire body mass is involved. When absorbing a blow, it reverses the process by soaking up the initial force, distributing it, and then gradually stiffing at the cellular level where the cells, rather than all the resistance landing on a local area. The bone breaking impact, rather than focused where the blow landed, will be he resisted by all your cells in a wave that spreads from the impact cite to a wall of billions of cells throughout the body, acting as perfect hydraulic shock absorbers, take up the blow. You go with the flow. Much of what seems unexplainable about the forces generated in martial arts are readily explained when the body is understood as a biotensegrity structure rather than as the common western post and lintel model.

The concept that the body is a tensegrity structure is not just a convenient model for martial arts practitioners. A turf toe injury in a quarterback will keep him from throwing a long pass.  The quarterback throws from his foot, not just his arm. We know that biologic tissues characteristically behave as nonlinear and visco-elastic material. In fact, this nonlinear behavior has been felt to be an essential quality of living tissue. Different researchers in different parts of the world have demonstrated evidence that the entire fascial network is interconnected so that a continuous tension network is known to exist within the body. We also know that at least some of the joints, like the shoulder girdle, transmit their loads through the tension of the soft tissue and not the compression of the bones. There is mounting evidence that this is the way all joints work. It is difficult to let go of concepts that have been part of us since childhood. The post and lintel lever system has intuitively been our model of how the body mechanically functions. On the other hand, we really know better. Just watch any child first learning to throw a ball. Our first throws are done as if the arm is a separate structure, detached from the body. We soon learn that to throw a ball, you must put your whole body into it as the football quarterback does. We just never had a model to understand what we were doing. Biotensegrity gives us that model. 2010 Stephen M Levin

———————————————————–Dr. Stephen Levin’s research in Biotensegrity holds the view that the body is a tensegrity truss system with tension members provided by a matrix of connective tissues, ligaments, muscles, blood vessels, nerves and fascia.

In this model, the bones are considered as spacers, not weight bearers along with incompressible fluids giving shape and form to a soft tissue entity.

Water in its structured form is enclosed in the body in fascial compartments. It helps to provide shock absorption and holds shape of a tissue. The different densities of liquids contribute to their form as either a sol or gel.

Therefore, as we move from liquid state to a denser tissue determines how the tissue reacts. This effect carries on through all tissues from fascia to bone.

Polymers are clusters of molecules that again have tensegrous properties. When polymers are in fluid solution, they can withstand great pressures.

As a polymer, the fluid in the synovial sacs prevents the approximation of bones during weight bearing and their shock absorbency. This concept was researched by Dr. Levin in the mid 1970s.

During an orthoscopy of a knee under local anaesthesia, he kept the patient standing in a weight bearing posture through the support of a tilt table. His findings demonstrated that as long as the ligaments were held intact then the joint surfaces of the knee crura could not be approximated.

Under Newtonian principles of weight bearing structures, this would never be possible. These same principles apply to all structures and tissues in the body. In the visceral system, the organs must position themselves in a closed fluid system. Some organs are held in place by the aid of negative air pressure suction and others by fascial and ligamentous attachment.

They are subjected to the forces of compression and tension as we move around and as the organs function as air or fluid movers or digesting foods. The weight bearing and movement behaviour of organs is known as turgor. In this model, the organs can expand and have mobility and motility qualities and interact with all their peripheral attachments.

The serous fluids that lubricate the space between organs allow an omni directional fluid shape sharing ability. When this fluid has the quality of a gel it acts as a buffer or spacer and a shock observer. Stresses are absorbed through the tension members of the fascia supporting and surrounding the organs.

The fascia is a connective tissue forming a continuously interconnected system throughout the living body. It’s formed of liquid crystalline material and has the property of acting as a semiconductor. When fascia is moved, it produces tension under pressure, which generates a peizo electric field. Peizo-electricity comes from the Greek meaning pressure electricity. Oschman, J

 Stress to tissues can result in a crystallising of the tissue turning a gel state to a sol. This affects the viscosity of the fluid to a restriction of the normal mobility of two adjacent structures. This can restrict the movement of an organ resulting in its immune response and function being impaired.

This impoverishment can result in many symptoms on its downward spiral towards pathology.

Standard methods of evaluating the body were based on Newtonian physics but this model does not fit our upright bipedal movement against gravity.

Newtonian physics can measure and calculate the strength of structures and the stresses they become subject to.

Unfortunately, the body is still reviewed and described in outmoded mechanical anatomical terms. Until the concept of Biotensegrity, the laws describing anatomical movement were according to Newtonian principles.

The cells that make up the soft tissues in the body arrange themselves into geometric shapes that just keep repeating themselves.

When cells gravitate together, they are subjected to natural laws governing their grouping and shape. The law of closest packing is the most economical way of stacking organisms.

If you stack a number of balls in a box there will be space between the balls. In the law of closest packing, the balls could be arranged to fit as tightly as possible into the case. In the closest arrangement, you end up with forms of icosohedron shapes.

Because there are actually no joined structures the icosohedron is quite unstable. This

results in the icosohedron oscillating and generating an energy field. Levin. S

In the study of Biotensegrity, the smallest components of bone or tissue arrange themselves as icosahedrons. Icosahedrons form structures that can withstand compression or tension in any direction. They can stack to make large structures like a beehive construction.

 In a tensegrity structure, compression elements float in the interspace of the tension wires. In the body, this would relate to the vertebrae in the spine. Each subsystem (vertebrae, disc and soft tissue) would be a subsystem of the spines meta system, like the beehive analogy.

When viewed in this way you can understand their role in balancing tension and compression when stress is applied to the human frame. Extracts from Spine state of the Art Reviews Vol , No 2, May 1995, Hanley and Belfast, Philadelphia, Ed Thomas Deman M.D

Loads applied to the body distribute their pressure through the network of tension elements to create a balance. Even a pressure load to a small bone will distribute the load through the whole system.

A natural movement strategy in tensegrity truss architectural form is the closest explanation of nature’s laws at work in the human frame.

Bones floating in a compression, tension network can form into trusses and extend out from the body like a bridge. This makes the body a weight mover not a weight bearer. So in walking and especially when your on one leg, the balanced tension maintains the integrity. Hatsumi says that you must learn to float in your walk. Hatsumi (2003).

The ligaments and soft tissues are constructed with soft visceoelastic materials that behave non linearly Journal of Mechanics in Medicine and Biology Vol 2,3 and 4, 375-388 World Scientific Publishing Co.

The difference between a mechanical structure and a human in motion is this non- linear flexibility of choice in movement.

In Newtonian physics a four dimensional universe is often described as a giant clockworks in three dimensional space manifesting linear processes in time Power Vs Force D, Hawkins.

In other words, movement of a structure is determined by a concept of causality.

One-step sequentially leading to the next in mechanical formation.

The human frame is not ruled by this concept and is capable of nondeterministic, omni directional change inside of movements. This is like changing the formation of a step when you realise you are going to trip.

Pressure does not act locally on the tissue or follow a specific anatomical route along muscles or fascia. It follows to the depth of the tissue change and can act in a non-linear dynamic way that matches the tension/compression changes to the damaged tissue. This is brought about by the ability to palpate deeply into tissue without force feedback being a resistant force.

 

In the art of Shinden, he told us that our energy or intent must come from the heart to our thumb to instigate the change. My initial understanding of this concept was to be sincere and benevolent or your intent to initiate healing in the client.

Although this is important, more recent research has demonstrated that the heart is the main generator of electricity in the body in the form of energy. Science also tells us that energy can neither be created nor destroyed, only converted.

In the visceral approach, you are focusing on the tension of fascia around the organs. We need to integrate the concept of one point approach to a tensegrous structure changing sol to gel in the tissue matrix.

Dennis Bartram November 2004

Updated April 2005 ——————————————————————————

The mechanical anatomy of a cell  In trying to reestablish a physical view of biology, Ingber has shown that cells, far from being formless blobs, use tension to stabilize their structure. And he has demonstrated, through two decades of experiments, that tensegrity not only gives cells their shape, but helps regulate their biochemistry.

Every cell, Ingber notes, has an internal scaffolding, or cytoskeleton, a lattice formed from molecular “struts and wires” not unlike the rigid tubes and tensed cables of Snelson’s sculptures. The “wires” are a crisscrossing network of fine cables, known as microfilaments, that stretch from the cell membrane to the nucleus, exerting an inward pull. Opposing the pull are microtubules, the thicker compression-bearing “struts” of the cytoskeleton, and specialized receptor molecules on the cell’s outer membrane that anchor the cell to the extracellular matrix, the fibrous substance that holds groups of cells together. This balance of forces is the hallmark of tensegrity.

Tissues are built from groups of cells, which Ingber likens to eggs sitting on the “egg carton” of the extracellular matrix. The receptor molecules anchoring cells to the matrix, known as integrins, connect the cells to the wider world. Ingber’s group in Children’s Vascular Biology Program has shown that a mechanical force on a tissue is felt first by integrins at these anchoring points, and then is carried by the cytoskeleton to regions deep inside each cell. Inside the cell, the force might vibrate or change the shape of a protein molecule, triggering a biochemical reaction, or tug on a chromosome in the nucleus, activating a gene.

Ingber says that cells also have “tone,” just like muscles, because of the constant pull of the cytoskeletal filaments. Much like a stretched violin string produces different sounds when force is applied at different points along its length, the cell processes chemical signals differently depending on how much it is distorted.

“A growth factor will have different effects depending on how much the cell is stretched,” says Ingber. Cells that are stretched and flattened, like those in the surfaces of wounds, tend to grow and multiply, whereas rounded cells, cramped by overly crowded conditions, switch on a “suicide” program and die. In contrast, cells that are neither stretched nor retracted carry on with their intended functions.

Location, location, location Another tenet of cellular tensegrity is that physical location matters. When regulatory molecules float around loose inside the cell, their activities are little affected by mechanical forces that act on the cell as a whole. But when they’re attached to the cytoskeleton, they become part of the larger network, and are in a position to influence cellular “decision-making.” Many regulatory and signaling molecules are anchored on the cytoskeleton at the cell’s surface membrane, in spots known as adhesion sites, where integrins cluster. These prime locations are key signal-processing centers, like nodes on a computer network, where neighboring molecules can receive mechanical information from the outside world and exchange signals. “Adhesion sites are what’s important for major control of the cell,” Ingber says. “If you’re in one of these sites, you’re hooked up to a bunch of players, both mechanical and chemical. You can affect these players, which in turn affect a bunch of other players.”

Ingber offers the example of the oncogene src, one of the first genes known to cause tumors. This mutated gene doesn’t shut off – it sends unrelenting chemical signals telling the cell to grow. “But what’s interesting is that src is normally found on the cytoskeleton in the adhesion sites, near its signaling partners,” he says. “To produce a cancerous transformation, it must be at these sites because it needs to be integrated within the structure of the cell.”

Disease mechanics Based on these observations, Ingber believes that genes and molecules only partially explain disease origins. In fact, he asserts that many medical conditions are caused by a mechanical failure at the cell and tissue level. Examples include congestive heart failure, where the heart muscle loses its elasticity and becomes “floppy,” thus losing its pumping efficiency; and asthma, where changes in tissue mechanics cause the airway to stiffen, tighten and contract, increasing mechanical resistance and constricting breathing.

But often the mechanical basis of a disease is not so obvious. On an airplane not long ago, Ingber found himself sitting next to Jing Zhou, a researcher from Brigham and Women’s Hospital, who told him about her work on polycystic kidney disease, or PKD. In children with PKD, huge cysts form in the kidney tubules, eventually replacing much of the mass of the organ itself, and causing the kidneys to fail. Zhou’s lab had found a gene linked to PKD and localized it to a thin antenna-like structure sticking out of the kidney cell, known as the primary cilium. But she had no explanation for the finding.

Ingber pointed out that the cilium is designed to sense mechanical forces ¨ in the case of the kidney, the shear stress caused by urine flow. Normally, the force of the flow bends the cilium, triggering calcium to rush into the cell. He suggested to Zhou that perhaps cells affected by PKD have a faulty calcium signal and constantly “think” that shear stresses are high. This in turn might cause the tubules to enlarge more and more to accommodate the flow, eventually forming cysts. From this serendipitous meeting, a collaboration was born, and together, Ingber and Zhou showed that when the PKD-causing genes are disabled in mice, the “lever” of the primary cilium malfunctions and fails to trigger a normal calcium response.

Scientific heresy? Ingber has worked hard to defend the notions of cellular tensegrity and mechanical forces regulating cellular biochemistry. He recalls being publicly attacked while presenting at scientific meetings. But he also remembers an eminent scientist telling him, “If you’ve got them that upset, you must be on to something important.” And so Ingber returned to the lab bench. “I responded to my critics by devising experiments,” he says.

In 1993, his team reported in Science that when they used magnetic forces to literally twist the integrin receptors at the cell surface, the cytoskeleton stiffened in response to the stress and behaved like a tensegrity structure. In 1997, the team reported in the Proceedings of the National Academy of Sciences that tugging on the same integrin receptors causes changes in the cell nucleus. In 2000, a study in Nature Cell Biology demonstrated that mechanical stress at the cell surface causes the release of chemical signals inside the cell that kick genes into action. Tweaking receptors not linked to the cytoskeleton had no such effect. Other experiments have altered the extracellular matrix – making it alternately rigid or flexible – and documented effects on cell signaling and gene expression.

Nanotechnology and beyond Ingber’s study of tensegrity’s role in disease has helped him forge some unexpected connections. In 2003, he worked with Harvard physics professor Eric Mazur on a nanote chnology project, using a laser to obliterate a miniscule portion of a cell, a few billionths of a meter in size, without affecting surrounding structures. Ingber got involved because he sees the laser as a tool for cutting out a single structure in a living cell to explore its mechanical role. He has also delved into systems biology, a new field that uses computational approaches to explore how molecular parts organize themselves into a system whose properties cannot be predicted by the parts alone. Informed by tensegrity, Ingber hopes to understand how structural, mechanical, chemical and genetic factors combine to govern cell behavior.

He has also helped devise new approaches to tissue engineering, and even posits that tensegrity helps explain the origins of life. Observing that viruses, enzymes, cells, and even small organisms take geodesic forms like hexagons and helices, Ingber suggests that tensegrity is nature’s way of creating strong, stable life forms with minimal expenditure of energy and materials.

“Tensegrity has given me a path that goes deep and broad,” Ingber says. “I believe the greatest value comes when you cross barriers and boundaries, and get a new perspective and vantage point. I’m not afraid of following my own path.” Nancy Fliesler

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